Gestures using the arm and hand are a fundamental and universal form of nonverbal communication between humans. Human gestures such as pointing out an object, waving to say hello, or curling a finger to signal someone else to come closer are all examples of gestures that communicate meaning between humans. A gesture based Human Interface Device (HID) is a computer device that accepts input from humans and produces a corresponding command to the computer. These devices may be used in situations wherein a user desires an alternative to mouse, keyboard, touch pads, or other devices. However, creating human interface devices based on optical sensing of human gestures can be challenging for a number of reasons. For example, it can be difficult to distinguish the human hands/arms from the background, inanimate objects, or projected light. Once the human hands/arms are sensed, the computer can track their motion and interpret gestures to produce commands.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.